The Swift/UVOT began settled observations of the field of GRB 100728A 86s after the BAT trigger (Cannizzo et al., GCN 11004). We do not detect a new source at the enhanced Swift XRT position (Evans et al. GCN 11005). The preliminary 3-sigma upper limits for the finding chart exposures (FC) and summed images are: Filter T_start T_stop Exp(s) Mag (3-sigma upper limit) ------------------------------------------------------------- white (FC) 86 236 147 >20.54 white 578 7432 657 >21.16 u (FC) 299 548 246 >19.82 u 702 7021 490 >20.04 v 628 11695 1218 >20.06 b 554 7226 510 >20.37 uvw1 677 13337 1228 >20.62 uvm2 1255 12600 1337 >20.69 uvw2 604 7554 447 >20.19 ------------------------------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction corresponding to a reddening along the line of sight of E_(B-V) = 0.18 mag. All photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).